.main{
	width: 500px;
	height: 800px;
	border: 1px solid black;
	margin: 0 auto;

	position: relative;
}

.header{
	height: 100px;
	background-color: pink;
}
.content{
	height: 500px;
	background-color: skyblue;
}
.footer{
	height: 200px;
	background-color: lightgreen;
}

/*
	父>子		子选择器，通过父选择器寻找子选择器对应的标记，对子选择器设置样式
*/
.header>p{
	margin: 0;

	/*字体大小*/
	font-size: 30px;
}

.header{
	/*弹性容器*/
	display: flex;

	/*主轴方向对齐方式*/
	justify-content: space-between; 
	/*交叉轴方向居中*/
	align-items: center;
}


.content{
	font-size: 200px;

	/*弹性容器*/
	display: flex;
	/*主轴居中*/
	justify-content: center;
	/*交叉轴居中*/
	align-items: center;
}

.footer{
	display: flex;
	justify-content: space-around;
	align-items: center;

	font-size: 40px;
}

#myAlert{
	width: 100%;
	height: 100%;
	position: absolute;
	top: 0;

	background-color: rgba(0,0,0,0.8);

	font-size: 30px;
	color: #fff;

	display: flex;
	justify-content: center;
	align-items: center;

	display: none;

}






